Compass and calipees



UNITED sTATEs PATENT OFFICE.

JOHN E. EARLE, OF LEIOESTER, MASSACHUSETTS.

COMPASS AND CALIPERS.

Specification of Letters Patent No. 11,420, dated August 1, 1854.

To all whom 15 muy concern Be it known that I, JOHN E.` EARLE, ofLeicester, in the county of Worcester and State of Massachusetts, haveinvented certain new and useful Improvements in Compasses, Dividers,'orCalipers; and I do hereby declare the following to be a full, clear,

. method of opening, closing, and holding the legs of compasses orcalipers.

The lower extremity of the legs A, A, of the instrument, may be straightor curved, as may best suit the purpose to which they are to be applied.The upper parts B, B, being curved so as to receive the toggle arms O,O, by which the legs are operated. The toggle arms C, C, are pivotedatD, by a pin common to both, and upon which they may work in thedirection of the sweep of the legs of the instrument, while they shouldbe prevented from yielding in any other direction. The other ends of thearms O, C, are pivoted-one to each of the legs at a, athe legs at thatpoint being suitably countersunk to receive the ends of said arms, orany other' suitable hinged joint maybe made. The arms at D, are pivotedor hinged, to the lower end of a screw rod E, of suitable `length toallow for the full sweep of the legs of the instrument, said rod passingup through a bur or nut F, which has a female screw cut in it.

The bur or nut F, extends through the head or yoke Gr, to which the legsare pivoted or hinged at b, Z), and has upon its upper part whichprojects, above said head, a

milled thumb piece by which it may be turned-said bur being so connectedwith the head as that it may turn'therein without rising or falling withthe screw, by which means the legs may be operated either way and thescrew or bur which operates fthein, hold them from moving in bothdirect-ions, when properly set.

The forms of these several parts may be modified or changed withoutchanging the general principle of -the instrument, and I do not confinemyself to thev precise arrangement represent-ed, reserving the right tomodify so long as Ido not depart from the general construction of theinstrument.

Having thus fully described the nature of m'y invention what I claimtherein as new and desire to secure by Letters `Patent is- Thecombination of the hinged `arms O, screw rod E, and nut F, with thehinged legs of compasses or dividers, and calipers, for the purpose ofmoving or holding said legs in both directions anywhere within the lineof their sweep, substantially as described. i

. JOHN E. EARLE.

